One of the easiest, most effective ways to start talking about sex with young kids is to read a book with them. My favorite is “Where Did I Come From?” by Peter Mayle. It’s been around for a while—for good reason–and it’s suitable for ages 3 to 10.

Its cartoony illustrations of a pudgy, anatomically correct couple make it easy to giggle, and the book talks about how grownups “get red in the face” when they talk about making babies. But what’s really important is that it uses correct terms (penis, vagina) and covers the hardest topics for most parents: penetration, pleasure, and orgasm (“a tremendous big lovely shiver”). Once you’ve conveyed that info, everything else is easier!

I used this book with my kids when they were quite little and often lent it to friends. When my younger child was 6, I realized that the book had gone missing, bought another copy, and read it to her at bedtime. At the time, she was learning in school about the difference between facts and opinions. She was very attentive as we read the book. When I finished, she looked at me with wide eyes and said, “Mommy, there are a lot of good facts in that book!”

Of course, we read the book other times that month and over the years. Because getting a book for your child isn’t enough; you also have to build from that into an ongoing conversation. Parents should have two goals: To make sure their kids have accurate information about sex, and to become a source of information and advice. The talks you start early will pay off hugely by the time your child hits middle school. If you haven’t started yet, start today!